科 目:投資與理財( B ) 組 別:第一組 組 長:陳慧茹 組 員:劉智仁 王郁涵 林沴君 賴怡靜 蔡宛珊 徐郁婷 陳柏辰 林昭寬
EXPERT SYSTEMS WITH APPLICATIONS 34 2008 IEEE 69721033 陳郁婷 A formal modeling platform for...
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Transcript of EXPERT SYSTEMS WITH APPLICATIONS 34 2008 IEEE 69721033 陳郁婷 A formal modeling platform for...
EXPERT SYSTEMS WITH APPLICATIONS 34
2008 IEEE
69721033 陳郁婷
A formal modeling platform for composing web services
Introduction
Service requesters regard most Web services as outsourced applications 不保證 connectivity and reliability 整合困難
The Web services technology stack still lacks a composition standard 互不相容
a composition must consider non-functional QoS issues more than functional QoS issues such as workflow reliability
Petri Nets-based Composing SCMP (Service Composition Modeling Platform)
Petri Nets
PN = (P, T, F, M, W) P : a set of places. T : a set of transitions that represents the set for
tasks, processes, activities, or events. F : a set of arcs used to represents flow paths M : an initial marking (M0, …… ,Mn) W : a set of arc weights denoting how many tokens
are consumed from a place by a transition
Web Service Petri Net
WSPN(Web Service Petri Net)WSPN = (P,T, F, Y, A)
P : a set of places →P = {p1,p2, . . . ,pn} T : a set of transitions →T = {t1,t2, . . . ,tn} F : a set of arcs → Y : a set of types →Y = {y1,y2, . . . ,yn}
BP : base place SIP : service input place SOP : service output place
A: P→ Y : association of places to types
SCMP (Service Composition Modeling Platform)
A visual editing module defining a conceptual service composition model using
the Petri Nets-based mechanism.A script language translation module
translate a conceptual model into a preferred composition script language.
A workflow measurable module employs evaluation algorithms to validate
nonfunctional workflow properties of Web services compositions.
•service finderUniversal Description, Discovery and Integration (UDDI) business registry (namely, the UBR)
•description document loader mechanisms
•WSFL and BPEL4WS language transformation•translator employs XSLT and XPath • specify elements and their
relationships•可 link 到 workflow engines• load the composition scripts • Test the execution results
•translate :• conceptual services
composition ↓PNML (in XML)
• Safeness : • if it has no more then one
token of a Petri Nets• Coverability tree
algorithm•Deadlocked : • if no transitions are
enabled• transitive matrix
algorithm•Reachable : • if it can be generated by
a sequence of transition firings beginning at the initial marking
PNML code document
<place id = ‘‘i1’’><name><text>newsRequest</text></name></place> <place id = ‘‘o1’’><name><text>newsResponse</text></name></place> <place id = ‘‘i2’’><name><text>englishNews</text></name></place> <place id = ‘‘o2’’><name><text>translatedNews</text></name></place>
<transition id = ‘‘op1’’><name><text>ProcessSRL</text></name></transition>
<transition id = ‘‘op2’’><name><text>BabelFish</text></name></transition> <transition id = ‘‘t1’’><name><text>Sequence1</text></name></transition>
<arc id = ‘‘aiop1’’source = ’’i1’’ target = ‘‘op1’’> . . . </arc> <arc id = ‘‘aopo1’’source = ’’op1’’ target = ‘‘o1’’> . . . </arc> <arc id = ‘‘aiop2’’source = ’’i2’’target = ’’op2’’> . . . </arc> <arc id = ‘‘aopo2’’source = ’’op2’’target = ’’o2’’> . . . </arc> <arc id = ‘‘aot1’’source = ’’o1’’target = ’’t1’’> . . . </arc> <arc id = ‘‘ati1’’source = ’’t1’’target = ’’i2’’> . . . </arc>
Conclusion
SCMP 不需要很多時間及技巧就能建構一個健全的 service
composition GUI 介面加快建構速度
未來 讓 SCMP 能連線到適當的 workflow engines 加入更多的 Petri Nets mathematical algorithms 或
formal analysis methods 來確認各種的 QoS properties.